Codec is based on original method of audio compression, which doesn't use patented audio compression algorithms (MP3 and others).

ALF2 CD Audio Codec is implemented as standard Windows ACM driver. It allows to use well known program, for example such as Winamp, Windows Media Player, CoolEdit and others for playback and editing compressed audio files.

Main features of ALF2 CD:

It is a free distributed format. Developers don't require any fee for using this format.
High encoding speed. Time of encoding of 1 minute of high quality music (44100 Hz, 16 bit, Stereo) is approximately 10-15 seconds on Pentium II, 300 MHz, RAM 64 Mb.
High quality of compressed signal.

Well, quality at 512kBps is a little worse than mu- or A-Law (706k bitrate), but is quite inflexible (only 44k1 stereo) and unknown to about anybody. It does seem to be lots better than M$ ADPCM at 384 kbps, but then I guess it'd be better to mux 320k cbr mp3.

Still, when testing unknown (high-bitrate) codecs, what samples should I use (now I used some Megadeth ) and what to pay attention to?

Well, you have to test all kinds of test tracks, although it could be that NCT ALF2 ain't psychoacoustics based codec, because the bitrates offered are so high.
I have not tested this, but I could imagine that pre-echo is not an issue here.

Well, I compared by inverse mix-pasting the encoded samples on top of the original (CoolEdit), and measuring the noise. It behaves in the same way as A- & mu-Law encoding - pulse code modulation I guess.